Electronic tube



Jan. 4, 1949. THOMAS 1 I 2,458,223

ELECTRONIC TUBE Original Filed July 3, 1959' a 5.33. 13 r m a I E l/ l I 11A I IIINVEIQTOR Patented Jan. 4, 1949 ELECTRONIC'TUBE Albert G. Thomas, Lynchburg, Va.

July 3, 1939, Serial No. d this application May 15, 1943, Serial No. 487,175

Original application 282,733. Divided an 7 Claims.

This invention relates to electronic tubes, and is a division from my abandoned application, Serial No. 282,733, filed July 3, 1939.

An object is to provide a tube to produce high frequency pulsations or oscillations.

Another object is to provide a high frequency tube of simple construction.

A further object is the provision of a tube capable of producing oscillations of extremely high frequency.

Other objects will appear in the specification.

In the drawings:

Figure l is a sectional side elevation of an ultra high frequency tube with hollow cathode construction.

Figure 2 is a sectional side elevation of an ultra high frequency tube with a hollow oscillator.

Figure 3 is a side sectional elevation of an ultra high frequency tube with in-built resonant circuit.

Figure 4 is a side sectional elevation of a hollow electronic resonator or oscillator.

Figure 5 is a side sectional elevation of another hollow oscillator which can be used with one or more of the previously designated tubes.

Figure 6 is a side sectional elevation of another form of hollow electronic oscillator.

In Figure 1, tube I has anode 2, grid 3 and cathode 4 which is shown as indirectly heated but which can be merely a hot wire, a photo emissive surface, or otherwise. Metal housing 5, preferably of cylindrical shape, is placed around cathode 4 and may be insulated from it. Opening 6 is provided in the face of housing 5 to allow electrons to pass out toward anode 2. The interior surface of housing 5, or areas of it, is preferably covered with barium oxide or similar substance that will emit a copious supply of electrons when heated. Housing 5 may be heated from cathode 4 by means of surrounding resistance coil 1 with leads 8 and 9 brought out of the tube. In the latter event the magnetic field produced by coil 1 will assist in directing electrons toward opening 6, if the various dimensions and variables are properly chosen.

Cathode 4 can be of small area to form practically a beam of electrons directed toward opening 6. Suitable accelerating and beam focussing rings can be placed inside housing 5 if desired, the leads for which can be brought out by means of insulation bushings. Grid 3 can be positively charged to assist in pulling electrons out of opening 6. This grid may consist of a very small area or of a point electrode if desired.

Heating of housing 5 will cause a cloud of elecu tion to modulate trons to exist, through which the beam from cathode 4% will pass. The passage of the beam of electrons through the electron cloud will cause very rapid oscillations of the cloud similar to. air vibrations in a whistle. T Therefore a rapidly pulsating beam of electrons will issue from opening 9 and will travel to anode 2. High frequency current can therefore be generated in this manner. The frequency of fluctuation will depend upon the dimensions of housing 5, the density of the cloud, and upon the beam speed. Anelectron gun can be substituted for cathode 4 so that high speed electrons will be projected into the cloud. A number of perforations 6 may be employed instead of one.

A further tendency to rapid oscillation will occur since the electron cloud will tend to crowd through opening 6 due to mutual electron repulsion. This effect is similar to steam issuing from an orifice. If desired, the outside of housing 5 may also be coated to emit electrons so that the jet of electrons issuing from opening 6 will be discharged into a cloud of electronsin tube l, which cloud will be set into rapid vibrathe output, current. at high tube l maybe of tubular Housing 5 may frequency. The actual shapeor any convenient shape.

be grounded or made positive relative to cathw ode 4.

In Figure 2, tube Ill has anode H and cathode I2. Electron accelerating and beam forming elements l3 and I4 are placed at progressively higher potentials relative to cathode l2 and have central openings as shown so that a beam ofelectrons is shot through central openings [5 and IB in opposite faces of cylindrical housing H. The

interior of this housing is coated with bariumoxide, thorium, or other material to produce .a copious supply of electrons when the housing is heated by means of surrounding resistance coil it which has exterior leads l9 and 20.

The electron cloud in housing M will therefore be set into rapid vibration by the passing beam and the beam will consequently be modulated at high frequency before it strikes anode H. A high frequency output will result.

If desired, rings openings l5 and i5, and can be charged slightly negative with respect to housing I! in order to prevent the escape of excessive numbers of electrons. Resistance 18 may be wound to produce a magnetic field or not, as desired. Housing: I! may be grounded to supply electrons and to prevent the building up of excessive charges, or it may be made positive relative to cathode l2, 1

2! and 22 may be placed near In Figure 3, tube 23 has anode 28 and cathode 24. Accelerating anode 25 with central opening for defining a beam of electrons is positively charged relative to cathode. This anode may also be used as a control grid if desired. Cylinder 26 is charged at higher positive potential and serves to accelerate and focus theelectron beam. Still .-another yqpositively charged anode 21, with small central opening, may beused to accelerate, focus, and define the beam so that it will pass through small annular rings 29 and 30 which are connected in series with small econdenser 3| and inductance 32 as shown. Inductance 33, with exterior leads 34 and '35, is in inductive relation to inductance32. The rings 29 and 30 can be placed sufficientlyclose together so that the capacity between them will make condenser 3I unnecessary, in which case inductance 32 and the capacity between the rings willform a resonant circuit. If then the electron beam is broken-up into groups 'of-electrons and if these groups pass th'rough rings '29 and 38 at intervals so that oscillatory currents in the tuned .ring

circuit :are properly reinforced, an extremely rapid oscillatory current will be induced iIlPCOil 3-3 and can be taken off leads '34 and 35.

Theloscillating currents in the 'ring circuit :will tend tomod-ulate the anode current .so that high frequency can also be taken on theanode circuit. This modulating effect may be .suificient to form a resonant condition which "will keep sustained oscillationsin'the ring circuit, but the :prior chopping ofithe-electron beam into-groups will certainly perform this function. The'zbeam may be broken up into groups in anumb'erof waystwo possibilities of-which are shown in the tubes or Figures 1 and2. Inductance 32may be coupled tothe gri'd circuit so that the beam will bemodulated at the frequency of oscillation of the ring circuit. 'Caremust be taken so that .the time of transit of the electron groups through rings :29 and "3 U will be in k'eepingwith the natural period (if-oscillation of the ring .circuitsolth'at a :resonan-t condition will exist.

Figure 4 shows a small electron ioscillatortank 36 with openingill. The interior of this tank is coated with barium oxide or the'like and the tank can "be hea'tedin any desired way so that-a .cloud of electrons will be formed inside the tank. This cloud will tend to escapethrough. opening 3! and if a loeam of electrons is directed across the opening as indicated'by the arrow, the electron cloud in the tank will be set into very rapid vibration on the 'same'principle that causes an :in a whistle or organ pipe to be set into oscillation. The oscillating cloud will then :cause a fluctuating ejection of electrons out of openingfi'l to modulate the electron beam at very -high .frequency. This tank maybe used in place of element Fl'in Figure 2. It may' be groundeddf :desired and may be surrounded'bya rheatingcoil, or may beequipped with fan interior filament or lamp to liberate photoel ectrons. The exterior electrons Inaybe .collected by the usual anode :or by an: additional positively charged .or grounded element. Such an additional element is shown at :38 and the high frequency circuit may the established between .:tank 36 .and element 38 as terminal cathode :and anoderespectively.

.In Fligure :5 itank .391has central aligned openings 4'0 and 41 through which L31 beam -:of ,elecin'onslnay be passed. :Plates 42 and-4-31are coveredrwithelectron emissive material :and are suitably heated. .Ihese-plates-may ibe insulated-from tank-l39zand-rmay berconnected at zonepoint by inples. Many changes made without departing from the broad concepts 4 ductance 44 and at another point by condenser plates 45, with suitable wires. Plates 45 are placed so that the electron beam, will pass between them and set the interior circuit into oscillation to modulate the beam at high frequency. Plates 45 may be covered with electron emissive material instead of plates #52 and 43, if desired.

Figure Gshowstankfliifi with aligned openings "4'1 and "48, off-set'as shown so that an unbalanced path for the interior electrons will exist. These oscillating electrons will then not be so liable to cancel the effect of each other as if the beam passed through the center. 2

I have shown and described electronic tubes which .I consider to be based 'of detail can obviously be I have disclosed.

'What 'I claim is: I

1. An electron discharge tube comprising, a cathode, an anode, athollow element intermediate saidtcathode and anode and having opposed openings therein facing respectively said cathode and said anode, and'ineans withinsaid tube and adjacent said hollowelement for heating saidhollow element.

2. An electron discharge tube enclosing a cathode,.an anode, a hollow element havingopposed openingstherein facing respectively said cathode and said anode, conductive materialof relatively low work function on a portion of the interior surface of said hollow element, and means adjacent said hollow element'for heating saidelement. v

3. An electron discharge-tube enclosing, a cathode, an anode, a hollow element having opposed open-ings'therein facing respectively said cathode andsaid anode. conductive material of relatively low work "function on'a portion of the'interior surface of said hollow element, means adjacent saidelement for heating said element, and a control member adjacent one of said openings.

4. An electron discharge tube enclosing, a hollow element having opposed openings therein, means within said tube and aligned with said hollow element for forming a beam of electrons and fordirect'ing said beam through said openings, and means within said tube and adjacent said element for hea'ting said element.

5. An electrondischarge'tube enclosing, .a hollow element having opposed openings therein, means within said tube and aligned with said hollow element .for forming a beam of electrons and ion-directing said beam through said openings, conductive material of relatively low work function on .a portionof the inner surface of said element, and means within said tube and adjacent saidelement for heating said element.

.6. An electron discharge tube comprising, a hollow conductive elcmenthaving opposed openings therein, -means within said tube. for forming a bearnofelectrons and for directing said beam through said-openings, material work functionon .a-portionof the inner surface of said-element, and a .coil .for carrying current around said element, theaxis of said coil beingsubstantiallyparallel withthe path of said beam.

.7. An electron discharge. tube comprising, .a hol-.

interiorsuriaceof said element, and means within upon novel princiof relatively low of electronsand fordirecting.

said tube and adjacent said element for heating said element.

ALBERT G. THOMAS.

REFERENCES CITED The following references are of record in the 5 file of this patent:

UNITED STATES PATENTS Number Number Number Name Date George Oct. 1, 1940 Hahn Nov. 26, 1940 Heil Mar. 18, 1941 Varian et a1 "Mar. 10, 1942 Linder June 2, 1942 George Sept. 8, 1942 Linder Mar. 23, 1943- Tunick Dec. 21, 1943 FOREIGN PATENTS Country Date Great Britain Sept. 8, 1932 

